1. Field of the Invention
The present invention relates to a plasma display panel (PDP) and a method for manufacturing the same. More particularly, the present invention relates to a manufacturing method of a PDP in which align marks are maintained in a discernible state, and to a PDP made using the manufacturing method.
2. Description of the Related Art
A PDP is a display device that realizes the display of images through excitation of phosphors by plasma discharge. That is, predetermined voltages are applied between two electrodes mounted in a discharge region of the PDP to thereby effect plasma discharge therebetween. Ultraviolet rays generated during plasma discharge excite phosphor layers that are formed in a predetermined pattern, thereby realizing the display of images. The different types of PDPs include the AC-PDP, DC-PDP, and hybrid PDP.
A conventional PDP includes a lower substrate and an upper substrate provided opposing one another with a predetermined gap (i.e., discharge gap) therebetween. A plurality of address electrodes are formed on a surface of the lower substrate opposing the upper substrate. The address electrodes are formed in a stripe pattern substantially along the Y direction. A dielectric layer is formed on the lower substrate covering the address electrodes, and a plurality of barrier ribs are formed on the dielectric layer. The barrier ribs define discharge cells, maintain the discharge gap, and prevent crosstalk between the discharge cells. A phosphor layer is formed between each adjacent pair of the barrier ribs covering the dielectric layer therebetween and side walls of the barrier ribs.
Formed on a surface of the upper substrate opposing the lower substrate are a plurality of display electrodes. The display electrodes are formed substantially along the X direction, that is, substantially along a direction perpendicular to the address electrodes. A dielectric layer and an MgO protection layer are formed on the upper substrate covering the display electrodes.
During manufacture of the PDP, align marks are formed and used as reference points in aligning the lower and upper substrates prior to sealing together the same, and in performing an exposure process. An electrode paste is typically used for the formation of the align marks during the formation of bus electrode (i.e., the display electrodes) in the case of the upper substrate, while an electrode paste is typically used for the formation of the align marks during the formation of the address electrodes in the case of the lower substrate. In recent times, however, a laser has been employed to form the align marks.
It is preferable that none of the elements of the PDP (or portions thereof) are positioned over the align marks in order to ensure full visibility of the align marks. Accordingly, a screen mask must be used during manufacture of the dielectric layers that does not leave the align marks exposed in order to ensure that the dielectric paste is not deposited on the align marks.
However, during drying and baking of the dielectric paste, the align marks, which are exposed during these processes, become oxidized and discolored. This makes the align marks unclear, and therefore causes difficulties in the alignment of the lower and upper substrates.